Interdependence of the mind and body is paramount in the context of Type 2 Diabetes Mellitus (T2DM), as day-to-day cognitions and behaviors have direct implications for disease management and for potential complications. Cognitive representations of self-efficacy for prescribed treatment regimens strongly affect behavioral adherence; which, in turn, influences physiological functioning. Patients' successful and failed efforts at disease management are shaped by significant others, such as the spouse. Spouses may engage in strategies to support patients' efforts, or to control (i.e., regulate) such efforts. The overarching goal of our proposed investigation is to examine the influence of spousal involvement (support and control) on the interrelationships among cognitive, behavioral, and physiological components in patients' management of T2DM. Our dyadic study will: 1) examine associations among patient efficacy, adherence to dietary behaviors and medication usage, and diabetes outcomes; 2) examine the effects of spousal support and spousal control on the cognitive, behavioral, and physiological components of T2DM, and whether the influence of spousal involvement on patients' diabetes outcomes changes over time; and, 3) identify gender differences in spouses' involvement in patients' disease management, and the resultant cognitive, behavioral, and physiological responses of female and male T2DM patients. We will follow 120 older T2DM patients and their spouses over 12 months. We will combine intensive daily diary assessments to detect the antecedents and consequences of patients' day-to-day disease management with annual and mid-year interviews and medical assessments to detect changes in the nature and effectiveness of spouses' involvement and changes in patients' diabetes outcomes.